1. Field of the Invention
The present invention relates to a modification of the invention disclosed in my depending application U.S. Ser. No. 10/165,458 filed on Jun. 7, 2002 which discloses a novel and efficient system for preventing the entry of ground moisture into so-called crawlspaces of buildings such as homes. Moisture is very damaging to wood structural support members of buildings and is absorbed by such members from the ground and from moist air in contact herewith.
As disclosed in U.S. Ser. No. 10/165,458, the disclosure of which is incorporated herein, many buildings and homes are built without basements, and are elevated a few feet above the ground on support members such as stone, poured concrete or concrete block walls. In many cases the crawlspace between the ground surface and the wooden floor beams or joists of the house is at a level below the level of the surrounding soil, or below the level of saturated soils in wet weather, so that water flows into and is absorbed up through the floor of the crawlspace, usually a dirt surface, from adjacent ground areas of higher elevation and up from the sub-soil. Such water is drawn into the headroom of the crawl space in the form of water vapor and penetrates the wooden structural members of the building, causing wood rot, mold, odors, attraction of ants and other insects, rodents etc. Insects, particularly subterranean termites, cause tremendous amount of damage and loss of property value to wooden homes and businesses, especially in certain areas of the United States. They migrate up from below ground over foundations, support members, conduits, etc., in contact with the ground, in search of moist wooden structural members which they infestate and digest causing eventual disintegration and collapse.
2. State of the Art
Copending U.S. Ser. No. 10/165,458, filed Jun. 7, 2002, discloses a novel and effective system for encapsulating a crawlspace against the entry of sub-soil water vapor, mold and insects through the crawlspace floor and walls and into wooden structural members. The system of the copending application comprises applying over the dirt floor of the crawlspace a continuous sealed plastic film barrier layer, and extending the barrier film vertically-upwardly to cover and seal the interior peripheral walls enclosing the crawlspace to an elevation at least slightly greater than the elevation of the ground in contact with the exterior surfaces of the peripheral walls and preferably to the tops of the peripheral walls. This encapsulates the dirt surface of the entire crawlspace against the penetration of external ground water or flood water and also sub-soil water, water vapor and insects such as termites through the plastic barrier film and into the crawlspace atmosphere where they can come into contact with wooden structural members.
While the encapsulation system of copending application U.S. Ser. No. 10/165,458 is completely effective for its intended purpose, it blocks access to the ground covered by the continuous barrier film. Such access is desirable or even necessary in some installations such as to enable gas or water meters to be read or, sewer cleanouts, or more commonly, to enable termite-control stations, such as Sentricon™ containers, to be serviced periodically. The Sentricon™ and other like bait station systems are in widespread use in areas where subterranean termite infestation is common, for the early detection of and control of termites before they migrate into the home or building. Containers are buried beneath ground level and filled with a bait such as wood. The containers are opened and inspected periodically for the presence of termites, which can enter the container and eat the wood. If termites are detected, the moist wood is replaced with termite-control chemicals, and the procedure is repeated to keep the termites under control.
While the crawlspace encapsulation barrier film prevents the entry of subterranean termites through the film into the crawlspace, it does not prevent underground colonies of termites from growing and migrating beneath ground beyond the crawlspace and/or up through hollow block walls into adjacent areas of the home or building. The Senticon™ and similar bait-and-kill systems require the burial of a plurality of containers, spaced around the entire periphery of the home or building, including any crawlspace for maximum effectiveness. Also, other termite treatments involve spraying the dirt surface of the crawlspace with chemicals every 5 years or so, beneath the barrier layer.